I’m trying to simulate a fluid for a 250 frame animation, but it is outside of camera view for the first 100 frames. Is there a way to only bake/simulate it for the remaining 150 frames instead of the entire scene? just trying to cut down on bake times. I’ve done this with several animations already but there’s got to be a way to do this right? 
You can start the fluid at a start time that is not at zero (in the domain settings)
But blender needs to still know what the fluid will look like at that time in the future so its still needs to calculate this.
What the fluid will look on frame 2 will depend on what the fluid looks like on frame 1
What the fluid will look on frame 3 will depend on what the fluid looks like on frame 2
What the fluid will look on frame 4 will depend on what the fluid looks like on frame 3
What the fluid will look on frame 5 will depend on what the fluid looks like on frame 4
What the fluid will look on frame 6 will depend on what the fluid looks like on frame 5
What the fluid will look on frame 7 will depend on what the fluid looks like on frame 6
etc etc etc
You cannot just go from frame 1 to frame 7 in one step